Flame arrester



Nov. 2, 1954 Filed June 21, 1951 H. A. QUIST FLAME ARRESTER 2 Shet's-Sheet 1 R. HAROLD A. QUIST ATTORNEYS QulsT FLAME ARRESTER Nov. 2,1954 2- 5heots-Sheef. 2

Filed June 21, 1951 INVENTOR. HAROLD A. QUIST ATTORNEYS United StatesPatentOi' 2,693,294 FLAME ARRESTER Harold A. Quiet, Elkton, Ma,assig'nor to Sun Oil com:

pany, Philadelphia, Pa., a corporation of New Jersey Application June21, 1951, Serial No. 232,841

'7 Claims. (Cl. 220-88) the use of a'flame arrester a greater hazardthan if it,

were abandoned entirely. There is yet another point of viewwhichconsiders flame arresters satisfactory for use only where vacuumconditions are experienced and the movement of the relieving gas isinwardly through the arrester to the body ofvolatile liquid. Again, someuses restrict the season during which the arrester covers the ventingapparatus to the spring, summer, and fall seasons, removing the devicesduring the winter months to avoid the icing condition. Under theselimitations of mechanical defects and special uses, industry has ingeneral considered abandoning the flame arrester of the type underdiscussion or in greatly restricting its use to particular seasons andconditions; It is an object of this invention to provide a flamearrester for general and unlimited use which is maintained free ofclogging matter, yet is operative under conditions of both pressure andvacuum to break the travel of flame along streams of combustible gasmoving to and from storage receptacles to give positive and reliablefire protection. The present inventionincludes a housing in which anon-freezing, non-volatile liquid with cleansing properties ismaintained at a predetermined depth. A recipro-' cating flame arrestingmember of. the tubular type is pivotally positioned to be cleansed andmaintained in safe operable'condition by this liquid. In the housing,above vthe liquid. level, gas transmitting conduits are placed to directthe flow of combustible and relieving gases in a path to and from thestorage tank through the housing body. The flame arresting member is sopositioned as to reciprocate in response to conditions of eitherpressure or vacuum in the storage tank to which it is attached, therebycausing a washing action in the liquid and movement to a position acrossthe flowing gas stream during the relief period.

In order that a better understanding of the invention may be had,references are made, to the following detailecll1 description and to theaccompanying drawing in whic Figure l is a plan view of the device withthe cover partly broken away. I v

Figure 2 is an elevation in section along line '22 of Figure 1. V

Figure 3 is a sectional elevation along line 3-3 of Figure 1.

Figure 4 is a sectional elevation of a part of Figure '3 along the line44.

Figure 5 is a sectional elevation showing operation under vacuumconditions.

Figure 6 is a sectional elevation showing operation under pressureconditions;

, The preferred embodiment of a flame arrester of the type described.which overcomes the enumerated objections and will operate equally wellfor both pressure and vacuum relief conditions, is shownin Figures 1 to4 2,6932% Patented Nov. 2, 1954 inclusive to which reference is nowmade. The housing 10 is designed to hold a body of liquid 12 maintainedat an operating level as shown. Reservoir devices for maintaining liquidlevels in housings for sealing purposes are well known. As such a deviceforms no part of the present mechanism and is not claimed, a descriptionof such a sub-element is omitted. A flame arrester member 14 of thetubular type is pivoted as at 1616 so as to be totally submerged beneaththe level of liquid 12 when in the inoperative position and also torotate into operating position as later discussed and shown in Figures 5and 6. The flame arrester member 14 is of the multiple capillary passagetype readily constructed by assembling corrugated aluminum plates cut toproper length and width and joined together so as to form a tubularstructure through which the relieving gases must pass. This structure iswell known in the art and is illustrated and discussed, for example, inthe patent to Steward, Number 958,944, issued May 24, 1910. Theperiphery of the flame arrester member 14 is formed to fit closely tothe interior of the housing so as to prevent the flame of a burningcombustible gas from traveling unobstructedly along the stream of thisinflammable gas back into the storage tank 18 during the relievingoperation.

In the preferred embodiment, the flame arrester housmg 1!) is connectedto a venting mechanism, such as a pressure control valve showndiagrammatically as at 20 which is, in turn, connected to the storagetank 18 by a conduit 22. Another conduit 24 connects the ventingmechanism 20 to an opening 26 in the housing 10 of the flame arresterabove the level of the liquid 12. Another opening 28 in the housing isadapted to receive the conduit 30 which is open to the atmosphere orconnected to another conduit as desired. The openings 26 and 28 are botharranged above the level of the liquid 12 so as to direct the stream ofrelieving gas in either direction across the housing above the body ofthe liquid.

The top 32 or the housing wnich forms the upper closure for the path ofthe relieving gases above the liquid level is shown as arched in thesectional elevation of Figure 2 and as rectangular in shape in the planview of Figure 1. This is the form of the preferred embodiment andrepresents the simplest type and probably the least expensive tomanufacture. A circular device in plan with a domed top will be readilyrecognized as an acceptable form and suggests other variations in shape.However, the form adapted for use requires only that the reciprocableflame arrester member be of such shape and so positioned as to move fromwashing engagement in the cleaning liquid to completely intercept thestream of relieving gas under conditions of either vacuum or pressure asthat gas passes through the flame arrester housing. A further precautionto properly position the flame arrester member is taken by locatingstrips or ribs 34 and 36 inside the top 32 of the housing 10 to hold theflame arrester member 14 in the proper position to intercept the flow ofthe relieving gases and eliminate a peripheral area which might possiblytransmit flame.

To present a complete operating unit which can be adapted to any storagetank or other venting mechanism with the least alteration to existingequipment, the preferred embodiment is illustrated as including its ownactuatingmech'anism. It will be readily understood that where theventing device noted diagrammatically by the numeral 20 in our figuresis of a reciprocating type, the flame arrester member may be connectedto be actuated by the valve through use of proper linkage. Or, anotheralternative may be adopted, readily discerned by those versed in theart, and the actuating mechanism about to be described maybe separatedcompletely from the housing of the flame arrester and used to operateone or more arresters. However, the spirit of the invention will befully understood through the description of the preferred device asillustrated where the actuator and flame arrester are in the samehousing on opposite sides of a separating partition.

The actuator of the illustrated preferred embodiment comprises anarcuate cup 38 which is operably mounted in a separate chamber 44 underthe cover 32 of the flame arrester housing 10. This is facilitated by apartition 48 projecting downwardly from the top 32 of the hous ing 10 toseparate the actuator chamber 44 from the flame arrester chamber herenoted as 46. This construction is clear in Figure 3 of the drawing. Thevpivot axis 16 of the flame arrester member 14 is also shown in thisfigure as having a suspension point in the partition 48. A feature ofthis partition is its location whereby it is sufficiently submerged inthe liquid 12 to prevent the escape of relieving gases from chamber 46into chamber 44 to obstruct the reciprocation of the actuator cup 38.The actuator 38 is adjusted as shown in Figures 2 and 3 to be in thenormal position when the arrester member 14 is substantially parallel tothe surface of the liquid 12 and totally submerged therein. Totalsubmergence of the arrester member insures complete protection of thedevice in the preferred embodiment, but washing contact is considered assuflicient under normal conditions. A bracket 42, or similar fastener,joins the actuator cup 38 to the pivoted supporting axis 16 to which theflame arrester member 14 is fastened. Pressure transmitting conduit 50connects the interior of the actuator cup 38 above the liquid level withthe vapor space of the storage tank 18. The conduit 50 is arced to curvewith the actuator 38 about the center of the common axis 16 of thearrester member. That part of the housing 10 which encloses this part ofthe device and noted as chamber 44, is extended to permit free movementof the flared end of the actuator cup 38, noted here by the numeral 52,which is necessitated in order to enclose the conduit 50 Without bindingduring operation as will be more clearly understood by reference to thelatter part of this specification. As has here been noted above, thepartition 48 is constructed to project downwardly into the body of thesealing liquid 12 to separate the housing 10 into twochambers, namely 44and 46, primarily to prevent the pressure of the relieving gases passingthrough chamber 46 from affecting the actuator operation. It will beevident that full movement of the actuator 38 in a clockwise directionas viewed in Figure 6, would be opposed by the liquid 12 which fills thechamber 44 as well as the chamber 46 to the same level. Consequently, itis necessary to include a receiving cup 54 which is positioned withinthe liquid body, as shown in all the figures of the drawing, to receivethe upper end of the actuator 38 as it rotates to lift the flamearrester 14 into the pressure venting position. This removes theinterference of the liquid body 12 and permits the complete operation ofthe device. A drain 56 is arranged to remove condensate and liquid whichmight drip from actuator 38 or otherwise be deposited in the cup 54,admits air at atmospheric pressure to assist in the vacuum operation,and relieves the chamber 44 of air during the pressure relievingmovement.

To those versed in the art, a study of the descriptive matter above,together with the figures of the drawing, will be sufficiently clear toindicate the full and correct operation of the disclosed device.However, in order to emphasize the advantages of the preferredembodiment, a complete description of the operation of the device underboth vacuum and pressure conditions will be detailed. Reference will bemade to all the figures of the drawing for a full understanding of theoperation, and particularly to Figures and 6 which show the position ofthe flame arrester member 14 in vacuum relief and pressure releaseoperations respectively.

Preliminary to using the flame arrester of this disclosure for cooeration with a pressure relief valve, it is necessary to etermine thesize of the device to afford the most eflicient operation. This canreadily be ascertained, as will be recognized by those versed in theart, by a consideration of the combined requirements of both the ventingdevice 20 and the size of the volume to be vented, shown here as thestorage tank 18. In unusual cases, it may be necessary to couple oneactuator to several flame arresters each of which is connected to arelief valve 20 or similar venting device. Once the combined assembly ofrelief devices and flame arresters to be used is determined, and thesize of the flame arrester is therefore known, the actuator for theproper operation of the flame arrester is easily designed.

To properly protect against fire and explosion, it is necessary that theactivation and complete operation of the flame arrester memberanticipate the passage of the" relief gases through the housing 10. Itwill be recognized by those versed in the art that this operation can beachieved by setting the venting mechanism 20v to follow the operation ofa more sensitively arranged flame arrester. Changes in the dimensions ofthe actuator as shown, particularly with reference to the size of thepressure transmitting conduit 50 and the relative cooperating area ofthe actuator cup 38, is an immediate solution to increased sensitivityof the flame arrester actuator. As a complement to this increasedactivity, the relief device 20 can be retarded by any well-known means,such as weights or pressure settings or any of the other well-knownmethods which are inherently characteristic of the valve or device used.

For a complete understanding of the operation of the flame arrestingdevice here disclosed in cooperation with a venting mechanism, thecombination of which is specifically suggested, reference is made to allof the figures of the drawing and particularly to Figures 5 and 6 whichshow the flame arrester operating under conditions of vacuum andpressure, respectivel .In the Figures 1 to 4 inclusive, the flamearrester is shown in the normal position when it is subjected to neitherpressure exhaust norvacuum relief. In this neutral position, the flamearrester member 14 is submerged in the non-freezing, noninflammablecleansing liquid 12, which may be glycol, glycerine, or a lightpetroleum oil specially treated. As the flame arrester is activeperiods, the surfaces of the arrester member are not subject to theclogging action of insects or the formation of ice which is a primaryobjection to devices of this type. Thus, the flame arrester isconstantly maintained in a clean and fully operable condition.

Under vacuum relieving conditions, the device assumes the position shownin Figure 5. As was indicated above, the size of the relative parts ofthe flame arrester for our. operations is selected to respond to thespecific tank conditions preliminary to the operation of the ventingdevice. The actuator is proportioned to recipro cate the flame arrestermember under the efiect of predetermined conditions in anticipation ofthe flow of relieving gas through the housing 10 above the surface ofthe sealing liquid. The certain response of an operable arrester memberin anticipation of the flow of the relieving gas by positioning thearrester member so that the gas is required to pass through it under allconditions of flow, is the assurance of safety.

Returning to a further consideration of Figure 5, the vacuum conditionsin the storage tank 18 may be induced as by pumping liquid out of thetank, the reduction of surrounding temperatures, or other reasons whichare well known to those who store volatile liquids. The negativepressure of the vacuum condition is transmitted to both the ventingmechanism 20 and to the disclosed flame arrester actuator equally and atthe same time. As already explained, the flame arrester actuator isdesigned to be more sensitive than the relieving devices and operates inadvance of the flow of any relieving gas through the housing 10. As thenegative pressure condition increases in the actuator cup 38, it isopposed by atmospheric pressure admitted through the drain 56,

creating the necessary operating pressure differential. The actuator cup38 moves downwardly over the conduit 50 into the sealing liquid. Theflared lower end of the actuator cup 38' permits the arcuate movement ofthe cup about the conduit 50 without obstruction. The fastener orbracket 42 connects the actuator 38 to the mounting. pivotal axis 16 ofthe flame arrester member 14 and reciprocates the member 14 to theposition shown.

in Figure 5 in contact with the rib 36. This movement from the body ofliquid illustrated in the preferred embodiment, or into contact with theliquid body suggested as a proper modification, causes a washing. actionto clean the transmitting surfaces of the flame arrester member. In thelifted position, the flame arrester member 14 fits closely within theperimeter of the top 32 of the housing. 10 and intercepts the flow ofrelieving gas (air in this case) through conduit 30' into the housing 10and throughthe conduit 24 and the venting mechanism 20 to relieve thevacuum condition in the tank 18. It will be noted by the arrows onFigure 5 which indicate the direction of flow of the relieving gas thatthere is a pressure drop between the side where the relieving gas entersthe flame arrester member 14 at the exit side. This difference inpressure assists in keeping the reciprocating flame arrester memberin-the during the relieving period. With the relieving of the totallysubmerged during these in-,,

proper arresting position pressure vacuum condition, and the balance ofpressure within the storage tank 18 is resumed, the actuator returns theflame arrester member to its neutral position into contact with theliquid 12 from which it starts. This reciprocating movement in responseto the movement of the actuator causes a washing action in the tubes ofthe flamearrester member and removes any foreign matter such as insects,condensation, or gummy substances which otherwise obstruct a stationaryarrester. 7 From the above disclosure of the relief of a vacuumcondition, the pressure exhaust condition as shown in Figure 6 will bereadily understood. Among the conditions of storage which build up apressure may be noted arising temperature, the pumping in of additionalfluids to be stored, and other familiar operations well known to theindustry. These operations cause an excessive increase in pressure whichis transmitted to the flame arrestor actuator 38 through the conduit 50and at a predetermined value lifts the inverted arcuate cup causing theflame arrester member 14 to assume a position against the rib 34 and inclose peripheral proximity to the top 32 of the housing 10. Anyopposition to the upward movement of the actuator cup 38 by air in thechamber 44 is relieved through the drain 56 which opens to theatmosphere. Except for the direction of reciprocation, the movement ofthe flame arrester member 14 is caused by the actuator 38 through itsattachment to the pivotal axis 16 by the connecting means 42 similarlyto the explanation made for this movement under vacuum conditions above.Having come to rest in contact with the rib 34, the flame arrestermember 14 is in position to intercept the movement of the relievinggases which pass from the tank 18, as shown by the arrows on Figure 6,through the venting mechanism 20 and enters the upper part of housingfrom the conduit 24. A pressure drop is established here as wasexplained above for the vacuum operation which also assists in firmlyholding the flame arrester member in operating position. The venting gasthen moves across the surface of the liquid 12, through the tubularstructure of the flame arrester member 14 as shown, and escapes from thearrester housing through the conduit 30 go either a collecting main orthe atmosphere as desire As was indicated above in discussing the vacuumcondition, the reciprocation of the flame arrester member; 14 by theactuator action causes a washing efiect which keeps the arrester memberclean and free of any clogging substances. Inasmuch as this. devicereciprocates in different directions, depending upon the vacuum andpressure condition to be relieved, this washing action is accentuated bycausing the liquid to wash through the tubular construction of the flamearrester member in several directions. As a result, the relief ofdangerous pressure conditions of storage is assured by a constantlymaintained free flame arrester passage.

From the above description, it will be apparent that an apparatus isprovided which overcomes the principle objections to flame arresters ofthis type. The apparatus is illustrated and described as the preferredembodiment of the invention presenting a safety device which isresponsively operative to the pressure conditions within the volume tobe relieved and which canont fail due to the obstruction of foreignmatter on its surface. It is designed to be anticipatively responsive tothe same conditions which actuate storage tank venting devices and isreadily connected to any of the known and accepted relief mechanisms.With little change, it may be directly attached to venting valves of therotating breather type and be caused to operate directly with such avalve. Under conditions Where the actuator of the venting mechanism isenclosed in thestorage tank, it may be readily coupled to such anactuator and made responsive to it. Although preferred to operate with aventing device as herein disclosed, it will be recognized that anarrester as described here can be, with'no inventive alterations, madeto respond to the pressure variations within a storage tank and may beoperated directly from the storage tank without an intervening pressureventing mechanism. An example of a condition favorable to the use of theflame arrester alone, without a venting mechanism is found wheresubstantially non-volatile, yet inflammable liquids are stored. Inshort, the cleansing and response features of the rotatable flamearrester '6 member in contact with a protective and cleaning bath arereadily-adapted to venting conditions of any kind.

It is obvious, therefore, that the construction and arrangement of thepartsmay be varied in many ways without departing from the spirit of theinvention. It is to be understood that the invention is no to be limitedto the'specific form and arrangement herein, except as such limitationsare specified in the following claims.

I claim:

'1. A flame arrester comprising a housing having a passage for the flowof gases therethrough, a cleansing liquid therein maintained proximatethe flow passage, a reciprocable flame arrester memberpivotally mountedin said housing in normally submerged contact with the liquid andreciprocable to obstruct the gas flow passage, and actuating meansoperably connected to reciprocate the arrester member in response to thegas pressures relieved through said housing.

2. A flame arrester comprising a housing, a vertically disposedpartition dividing the upper portion thereof into an arresting chamberand an actuator chamber, a cleansing liquid in said housing maintainedat an operating level to seal said chambers by engaging the dividingpartition, opposed gas flow vents in the arresting chamber above theliquid level, a reciprocable capillary flame arrester member pivotallymounted in the arresting chamber below the level of the cleansingliquid, said member being rotatable to intercept the flow of gas betweensaid vents, and actuating means in the actuator chamber connected toreciprocate the arrester member between the liquid and the flow of gas.

3. The flame arrester defined in claim 2 further characterized by theactuating means in the actuator chamber including an inverted cupoperably mounted in sealing engagement with the liquid therein, and apressure transmitting conduit opening into said cup above the liquidlevel.

4. A flame arrester mountable on a storage tank comprising an arresterchamber adapted to contain a cleansing liquid at a predetermined leveland having above said level an air vent, and alongside said arresterchamber an actuating chamber having an air vent, an inverted cup in theactuating chamber and a flame arrester in the operating chamber, bothpivotally mounted and swingable together on the same horizontal axis,and means adapted to afford gaseous communication between the tank andthe cup and the tank and the arrester chamber respectively; said flamearrester member being positioned, under conditions of balanced pressurebetween the tank and the atmosphere, to assume a horizontal position insubmerged contact with the liquid and under conditions of unbalancedpressure between the tank and the cup to be swung with the cup on saidaxis to project an end portlion of the flame arrester member above theliquid eve 5. The construction defined in claim 4 in which the flamearrester is pivotally mounted between its ends below said liquid leveland is swingable in opposite directions on its axisupon rise of tankpressure above, and fall of tank pressure below, atmospheric pressure,the air vent in the arrester chamber and the communicating means betweensuch chamber and the tank being located on opposite sides of thearrester chamber to thereby, under said conditions of unbalancedpressure, constrain flow of gaseous fluid through the end portion of theflame arrester member projecting into the space above said liquid level.

6. A flame arrester comprising in combination a housing having a gasflow chamber in the upper portion, a sealing liquid in*the lower portionforming the lower surface of the gas flow chamber, opposed gas flowvents in the gas flow chamber above the liquid level, a re ciprocablecapillary flame arrester member pivotally mounted to be submerged withinthe liquid in a normally horizontal position; an actuator housing havingan atmosphere filled space in the upper portion, a sealing liquid in thelower portion, an inverted cup mounted in sealing engagement with theliquid therein, a pressure transmitting conduit opening into said cupabove the level of the sealing liquid; and connecting means linking thereciprocable flame arrester member to the inverted cup to swing the samefrom the immersed position in the cleaning liquid to a position of gasflow interception between the gas flow vents in the arrester housing.

7. A flame arrester comprising a housing having a 7 vertical partitiondepending from the top thereof and dividing the upper portion into a gasflow chamber and an actuator chamber, a body of liquid in the lowerportion of the housing maintained at suflicient depth to engage saidpartition in sealing contact and operably separate the chambers therein,opposed flow vents in the gas flow chamber above the liquid level, aTeciproca'ble capillary flame arrester member axially supported in saidgas flow chamber, pivot supports for the axis of said arrester memberpositioned below the 'level of said liquid therein, an inverted actuatorcup in said actuator chamber operably suspended in sealing contact withthe liquid therein, a pressure transmitting conduit extending into saidactuator cup and opening therein above the liquid level, and connectingmeans coupling the arrester 15 2,587,943

member to the actuator cup whereby the arrester swings on its axis fromthe liquid to a gas flow intercepting position in the gas flow chamberin response to pressures affecting the cup in the actuator chamber.

References Cited in the file of this patent UNITED STATES PATENTSWiggins Mar. 4, 1952

